Corylus colurna - Turkish Filbert
Family - Betulaceae
Size - Medium grower to about 40 to 50' with a spread about 1/2 the height. Broad, pyramidal shape, full, very attractive tree. Formal appearance, very similiar to 'Bradford' Pear, but it doesn't have the drawbacks.
Foliage - Alternate, simple, broad, ovate, doubly serrated on the margins. Foliage can be a very dark green during the growing season, fall color seems to be non existent, yellow green, ratty looking, and dropping early.
Flower/Fruit/Seed - Flowers are 2 to 3" long male catkins. Fruit is a nut, 1/2" to 5/8" in diameter. Ours haven't born nuts as of yet.
Bark - One of the most interesting characteristics; spongy, corky, heavily ridged and furrowed on young trees, dingy gray-white in color. While in Portland Oregon, I noticed some 12" to 15" dbh Turkish Filbert, I believe outside the Japanese Gardens. The bark was woody and typical on the larger trees. Older bark becomes flaky and as scales fall off it exposes orangish-brown underneath.
Pests and Diseases - Supposedly is problem free, but I've had successive problems every summer in the nursery with what I believe is a foliage blight. Corylus avellana 'Contorta' is often affected by a blight and I experience the same problems with it. Foliage becomes lesioned, distorted and the trees begin to defoliate in late summer. In the nursery, foliage moisture is minimized as I use a spray emittor to each container. I'll be curious to see if the problem is lessened in the landscape. Many times problems are more severe in the nursery due to crowding and high humidity.
Landscape Use - Lawn, street tree use, its formal character could make it a substitute for 'Bradford' Pear where one needs this look.
Performance - 7 I believe it is a tree that has possible potential. The foliage blight really bothers me though and if it continues year in and year out in the landscape then the uses of this tree for this area will be limited. Other than this, it is supposed to be a tree that does well in hot summers and cold winters, is pH adaptable, and quite drought tolerant once established. Hardly ever seen or grown. It is difficult to propagate and for this reason alone it will probably never be very well know or used in the trade.